A vinyl chloride resin for paste processing (hereinafter, abbreviated as paste PVC sometimes) is ordinarily kneaded together with a plasticizer, a filler, a stabilizer or other compounding agents to prepare a paste PVC sol, and the paste PVC sol is used in a variety of molded products, for example, wallpaper, tile carpet and gloves by various molding method. Further, in the application of low processing temperature as paste PVC having a property excellent in gelation meltability for obtaining mechanical strength even at a relatively low temperature, a vinyl chloride/vinyl acetate copolymer resin obtained by copolymerizing vinyl acetate with vinyl chloride is known. Moreover, as a countermeasure for storage stability for a long period of time from the preparation of paste PVC sol to the processing, paste PVC having a small change with time in sol viscosity has been required.
As a method for producing paste PVC having a small change with time in sol viscosity, a method for producing a polyvinyl chloride resin for paste processing by a seed microsuspension polymerization using a specific surfactant has been proposed (see, for example, Patent Document 1).
In addition, a polyvinyl chloride resin composition in which a specific compound is incorporated into a paste PVC sol has been proposed (see, for example, Patent Document 2).